According to Dr. Burke, the symptoms haven't changed and should be addressed immediately. They include a fever over 100 degrees, a cough or sore throat, body aches and chills, and a runny or stuffy nose. The virus also spreads easiest through saliva droplets, and coming into contact with infected surfaces.

The good news, says Dr. Burke, is that this year's flu vaccine is a good match for preventing this strain from spreading.

The three most vulnerable demographics, says Dr. Burke, are those with chronic illness, the elderly, and young children, which Duluth Public Schools Nurse Kathy Hughes says makes sense given school–goers constant close proximity to one another.

"Kids just aren't always aware of their surroundings. They're busy talking, eating, [and] playing. As much as we try to impress upon them, 'you need to wash your hands, cover your cough, when you sneeze cover [your mouth] into your sleeve,' if you walk the hallways I'm sure you wouldn't always see that," said Hughes.

With one Duluth public school classroom reporting 5 illness–related absences on Monday alone, Hughes urges parents to recognize the symptoms and know when to keep their kids home.

"...and keep your child home for 24 hours after that fever, because if [they] have a fever, it [means] infection," said Hughes.

And, while frequent hand–washing and covering your cough can help stop the virus's spread, the most effective preventative measure, say officials, is still a vaccination.

"There's ample supply, it's very effective, and there [are] lots of options," said Dr. Burke.

...options that include a nasal spray for those needle–phobic Northlanders.

Officials emphasize that, if you believe you have the flu, try to quarantine yourself from the public as best as possible.

In particular, stay away from visiting family and friends in the hospital or in nursing homes until at least 24 hours after your symptoms have subsided.